Brand Name: ORBEST
Generic Name: Ornidazole
Preparation: 500 mg Tablet
Pharmacological Categories: Antiprotozoal, Antibacterial
Mechanism of Action (MOA)
ORBEST (Ornidazole) is a 5-nitroimidazole derivative active against protozoa and anaerobic bacteria. ORBEST is converted to reduction products that interact with DNA to cause destruction of helical DNA structure and strand. This leads to inhibition of protein synthesis and causes cell death in susceptible organisms.
Pharmacokinetics
• Absorption: Readily absorbed from gastrointestinal tract
• Peak Plasma Concentration: 3 hours
• Distribution: Widely distributed in body tissues and fluids, including the cerebrospinal fluid (CSF)
• Protein Binding: Less than 15%
• Metabolism: Hepatic
• Elimination Half-life: 12 to 14 hours
• Excretion: Urine, mainly as conjugates and metabolites and to a lesser extent in the feces
Indications and Dosage
• Amoebiasis: Adult: 500 mg BD for 5 to 10 days; Children: 25 mg/kg as a single daily dose for 5 to 10 days
o Amoebic dysentery: Adult: 1.5 g as a single daily dose for 3 days; Children: 40 mg/kg daily
o Adults >60 kg: 1 g BD for 3 days
• Giardiasis: Adult: 1 or 1.5 g single daily dose for 1 or 2 days; Children: 30-40 mg/kg daily
• Trichomoniasis: 1.5 g single daily dose or 500 mg BD for 5 days (both sexual partners)
• Anaerobic bacterial infections: intravenous infusion in an initial dose of 0.5 to 1 g, followed by 1 g daily as a single dose or in two divided doses for 5 to 10 days; oral therapy of 500 mg every 12 hours should be substituted as soon as possible.
Side Effects
Nausea, vomiting, constipation, metallic taste, furred tongue, glossitis, stomatitis, weakness, dizziness, ataxia, headache, drowsiness, insomnia, changes in mood or mental state such as depression or confusion, peripheral neuropathy, epileptiform seizures, temporary moderate leucopenia, thrombocytopenia, skin rashes, urticaria, pruritus, erythema multiforme, angioedema, anaphylaxis, urethral discomfort, darkening of urine, raised liver enzyme values, cholestatic hepatitis, jaundice
Contraindications
Hypersensitivity to ornidazole or to other nitroimidazole derivatives
Warnings / Precaution
• Peripheral neuropathy, transient epileptiform seizures and leucopenia have been associated with prolonged or intensive treatment.
• Clinical and laboratory monitoring is advised in patients if given for more than 10 days.
• Doses should be reduced in patients with severe hepatic impairment.
• Use should be avoided during pregnancy especially during the first trimester and with high dose regimens.
Drug Interactions
• Potentiates effect of coumarin type oral anticoagulants.
• Prolongs the muscle-relaxant effect of vecuronium bromide.
Pregnancy Category: C
Presentation
ORBEST: 10 X 10’s
